Meet Elf - one of my RoboPi + Raspberry Pi based robots!
I have a lot of the Magician 2WD chassis, and I thought it would be the perfect platform to evaluate inexpensive low power motor driver modules.
Recepie:
- RoboPi
- Raspberry Pi
- WiFi stick
- Magician 2WD chassis
- L9110S driver module
- breadboard - jumper wires
- HC-SR04 ultrasonic range sensor
Assemble & start playing :)
Right now, ELf is pretty simple, but I have this nice Raspberry Pi camera module for him...
More photos etc on the build log page at http://www.mikronauts.com/robot-zoo/elf-2wd-pi-robot/
I'd be happy to answer your questions about Elf here!
Tue Aug.14, 2014 Update
I am using Elf to test out my new Python library for RoboPi. So far so good :-)
Barring unforseen issue, I expect to release the v0.85 firmware/libraries/documentation next week, inlucding Python support.
This is a companion discussion topic for the original entry at https://community.robotshop.com/robots/show/elf-my-robopi-raspberry-pi-2wd-magician-wifi-robot
Python
so far - so good. Here isa random walk snipped:
# main program
RoboPi.RoboPiInit("/dev/ttyAMA0",115200);
for motor in range(lfwd,rrev+1):
RoboPi.pinMode(motor,isa.OUTPUT) # set motor control pins to output
while (1):
while (RoboPi.readDistance(sonar) > 200):
forward(255,0)
while (RoboPi.readDistance(sonar) < 201 ):
spin_left(255,1)
RoboPi.RoboPiExit()
Neat!
I’m working on my Magician chassis right now, though I’ll have to chop off a bit to make it balance.
Where can you buy them in blue?
Blue 2WD Magician
Thank you!
I make mine balance using the weight of the battery packs.
I ordered them a couple of years ago, I still have about 50 of the blue 2WD in stock.
I was trying to make a
I was trying to make a balancing bot out of them. Unfortunately this didn’t work, so I’m working on plan C now.
Thank you. And here I was hoping to get a new red, green, and blue one. I guess I’ll have to print something for that idea when my printer is finally shipped and wends it slow way here. It will probably arrive real soon now when I can’t do anything with it because Lee needs surgery and I have to take her to Cleveland.
My best wishes for Lee
I hope the surgery goes well!
I am not sure how well those yellow gear motors would work for a balancing bot, so please let me know if it works.
If you can’t find it in the states, and you need a blue one, pm me.
major Elf updates 
I was finally able to make some time to update my Elf build log
- wiring info and photos for the L9110S motor driver
- wiring info and photos for the HC-SR04 range sensor
- sample Python code for RoboPi controlling the motor driver via PWM and reading the range sensor
Elf: http://www.mikronauts.com/robot-zoo/elf-2wd-pi-robot/
RoboPi: www.mikronauts.com/raspberry-pi/robopi/
I welcome your questions and feedback!
Elf update: Raspberry Pi Camera & WiFi streaming
Today I’ve updated my Elf Raspberry Pi based robot’s build log with instructions on:
- adding a Raspberry Pi Camera
- adding MJPG-Streamer so Elf streams what he sees over WiFi
- adding a ramdisk for MJPG-Streamer so it won’t wear out the SD card
I hope you enjoy the Elf blog, and please feel free to ask any questions!
Elf Article Index
